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UV Radiation Exposure (uv + radiation_exposure)

Distribution by Scientific Domains

Medical Sciences	75%

Selected Abstracts

Screening of urocanic acid isomers in human basal and squamous cell carcinoma tumors compared with tumor periphery and healthy skin

EXPERIMENTAL DERMATOLOGY, Issue 10 2008
Juan Manuel Decara
Abstract:,Trans -urocanic acid is a major chromophore for ultraviolet (UV) radiation in human epidermis. The UV induces photoisomerization of trans -urocanic acid (tUCA) form to cis -urocanic acid (cUCA) and has been reported as an important mediator in the immunosuppression induced by UV. This immunomodulation has been recognized as an important factor related to skin cancer development. This is the first time that UCA isomers have been measured in epidermis of skin biopsies from patients with squamous cell carcinoma (SCC) and with basal cell carcinoma (BCC) and compared with the tumor periphery and biopsies of healthy photoexposed and non-photoexposed skin as controls. The UCA isomers were separated and quantified by high performance liquid chromatography. Analysis of UCA in healthy skin showed significant increase in total UCA content in non-photoexposed body sites compared with highly exposed skins. In contrast, the percentage of cUCA was higher in photoexposed body sites. Maximal levels of cUCA were found in cheek, forehead and forearm and lower levels in abdomen and thigh. No differences were found in total UCA concentration between the tumor samples and healthy photoexposed skin. However, differences were found in relation between isomers. Higher levels of cUCA were detected in SCC biopsies (44% of total UCA) compared with samples of BCC and that of healthy photoexposed skin (30%). These results suggest that the UV radiation exposure, a main factor in development of SCC can be mediated, apart from direct effect to cells (DNA damage), by immunosuppression pathways mediated by high production of cUCA. [source]

The implications of solar UV radiation exposure for fish and fisheries

FISH AND FISHERIES, Issue 3 2001
Horacio E Zagarese
Abstract Ultraviolet radiation (UVR) possesses three important properties that combine to make it a potent environmental force. These include the potential to induce damage: UVR carries more energy per photon than any other wavelength reaching the Earth's surface. Such highly energetic photons are known to damage many biological molecules, such as DNA and proteins. In addition, they can initiate a series of redox reactions to form reactive oxygen species (ROS), which cause oxidative stress to cells and tissues. The second property is ubiquity: owing to their dependence on light, primary producers and most visual predators, such as fish, are also necessarily exposed to damaging levels of UVR. Thirdly, the combined effect of UVR and additional environmental factors may result in synergistic effects, such as the photoactivation of organic pollutants and photosensitisation. In natural environments, the concentration of dissolved organic matter (DOM) and habitat depth are the two main factors controlling the degree of UVR exposure experienced by fish. Additional factors include vegetation coverage, particulate materials in suspension, pH and hydrological characteristics, and site location (latitude, elevation). The range of potential effects on fish includes direct DNA damage resulting in embryo and larval mortality, and adult and juvenile sunburn, as well as indirect oxidative stress, phototoxicity and photosensitisation. [source]

Ultraviolet radiation intensity predicts the relative distribution of dermatomyositis and anti,Mi-2 autoantibodies in women

ARTHRITIS & RHEUMATISM, Issue 8 2009
Lori A. Love
Objective Because studies suggest that ultraviolet (UV) radiation modulates the myositis phenotype and Mi-2 autoantigen expression, we conducted a retrospective investigation to determine whether UV radiation may influence the relative prevalence of dermatomyositis and anti,Mi-2 autoantibodies in the US. Methods We assessed the relationship between surface UV radiation intensity in the state of residence at the time of onset with the relative prevalence of dermatomyositis and myositis autoantibodies in 380 patients with myositis from referral centers in the US. Myositis autoantibodies were detected by validated immunoprecipitation assays. Surface UV radiation intensity was estimated from UV Index data collected by the US National Weather Service. Results UV radiation intensity was associated with the relative proportion of patients with dermatomyositis (odds ratio [OR] 2.3, 95% confidence interval [95% CI] 0.9,5.8) and with the proportion of patients expressing anti,Mi-2 autoantibodies (OR 6.0, 95% CI 1.1,34.1). Modeling of these data showed that these associations were confined to women (OR 3.8, 95% CI 1.3,11.0 and OR 17.3, 95% CI 1.8,162.4, respectively) and suggests that sex influences the effects of UV radiation on autoimmune disorders. Significant associations were not observed in men, nor were UV radiation levels related to the presence of antisynthetase or anti,signal recognition particle autoantibodies. Conclusion This first study of the distribution of myositis phenotypes and UV radiation exposure in the US showed that UV radiation may modulate the clinical and immunologic expression of autoimmune disease in women. Further investigation of the mechanisms by which these effects are produced may provide insights into pathogenesis and suggest therapeutic or preventative strategies. [source]

Global surface ultraviolet radiation intensity may modulate the clinical and immunologic expression of autoimmune muscle disease

ARTHRITIS & RHEUMATISM, Issue 8 2003
Satoshi Okada
Objective To determine if geoclimatic factors may influence the nature and frequency of dermatomyositis (DM), polymyositis, and associated autoantibodies around the world. Methods We assessed, in the first global evaluation of these conditions, the relationship between 13 geoclimatic variables that may modulate disease and the relative proportion of DM and its associated autoantibody anti,Mi-2, directed against an SNF2-superfamily helicase associated with the nucleosome remodeling and histone acetylation and deacetylation complex, in a global myositis population. Altogether, 919 consecutive patients from populations at 15 locations were studied. Results Univariate and multivariate analyses demonstrated that of the variables evaluated, surface ultraviolet (UV) radiation intensity (irradiance) most strongly contributed to the relative proportion of DM and was strongly related to the proportion of anti,Mi-2 autoantibodies (weighted r = 0.939, P < 4 × 10 -7 and weighted r = 0.69, P = 0.02, respectively). Published ethnogeographic immunogenetic allele frequencies imply that the striking differences in the proportion of DM- and DM-specific autoantibodies observed around the world are not the result of inherent global variations in known genetic risk factors. Conclusion These data suggest that UV radiation exposure may modulate the clinical and immunologic expression of an autoimmune disease in different populations around the world. [source]